Alkylation process



United States Patent 3,402,213 ALKYLATION PROCESS Armand J. De Rosset,Clarendon Hills, lll., assignor to Universal Oil Products Company, DesPlaines, Ill., a corporation of Delaware No Drawing. Filed Aug. 30,1966, Ser. No. 575,946

Claims. (Cl. 260-671) ABSTRACT OF THE DISCLOSURE A process for thealkylation of aromatic compounds With olefin-acting compounds using acatalyst comprised of a refractory inorganic oxide chemically combinedwith a metal subfluoride is disclosed.

This invention relates to a conversion process for the alkylation ofalkylatable aromatic compound into more useful compounds. Morespecifically, this invention is concerned with a conversion process forthe alkylation of an alkylatable aromatic compound with an olefin actingcompound utilizing a novel catalyst comprising a refractory inorganicoxide chemically combined with a metal subfluoride vapor.

It is therefore an object of this invention to provide a process for thealkylation of alkylatable aromatic compounds utilizing a novelalkylation catalyst.

A specific object of this invention is to provide a novel method and anovel catalyst for alkylating alkylatable aromatic compounds to providethe desired alkylated product in high yields.

One embodiment of the invention relates to a conversion process whichcomprises alkylating an alkylatable aromatic compound at a temperaturein the range of from about 0 to about 450 C. and a pressure in the rangeof from about atmospheric to about 200 atmospheres in contact with acatalyst comprising a refractory inorganic oxide chemically combinedwith a metal subfiuoride vapor.

Other objects and embodiments referring to alternative alkylatablearomatic compounds and to alternative catalytic compositions of matterwill be found in the following further detailed description of theinvention.

The process of my invention is applicable to the alkylation ofalklatable aromatic compounds including, for example, benzene, toluene,ortho-xylene, meta-xylene, paraxylene, ethylbenzene, ortho-ethyltoluene,meta-ethyltoluene, para-ethyltoluene, 1,2,3-trimethylbenzene,1,2,4-t-rimethylbenzene, 1,3,5-trimethylbenzene, diethylbenzene,triethylbenzene, normal propylbenzene, isopropylbenzene, etc. andmixtures thereof. Preferred alkylatable aromatic compounds are themonocyclic aromatic hydrocarbons, that is, the benzene hydrocarbons.Higher molecular Weight alkyl aromatic hydrocarbons are also suitable.These include those aromatic hydrocarbons such as are produced by thealkylation of aromatic hydrocarbons with olefin polymers and are used asintermediates in the preparation of sulfonate surface-active agents.Such products are frequently referred to in the art as alkylate, andinclude hexylbenzenes, nonylbenzenes, dodecylbenzenes,pentadecylbenzenes, hexyltoluenes, nonyltoluenes, dodecyltoluenes,pentadecyltoluenes, etc. Very often, alkylate is obtained as a highboiling fraction in which the alkyl group attached to the aromaticnucleus varies in size from about C to C Other suitable aromatichydrocarbons, which at specified conditions, depending upon the meltingpoint of the aromatic chosen, would be in liquid form, would includethose aromatic hydrocarbons with two or more a-ryl groups such asdiphenyl, diphenylmethane, triphenyl, triphenylmethane, fluorene,stilbene, etc. Examples of other aromatic hydrocarbons utilizable withinthe scope of this invention which at specified alkyl- 3,402,213 PatentedSept. 17, 1968 ation conditions, depending upon melting point of thearomatic chosen, would be in liquid form, include those containingcondensed aromatic rings. These include naphtha lene, alkylnaphthalenes, anthracene, phenanthrene, naphthacene, rubrene, etc. Ofthe above-metnioned aromatic hydrocarbons that could be utilized in theprocess of this invention, the benzene hydro-carbons are preferred, andof the preferred benzene hydrocarbons, benzene itself is particularlypreferred.

The olefin-acting compound, acting as the alkylating agent, may beselected from' diverse materials including mono-olefins, diolefins,polyolefins, acetylenic hydrocarbons, and also alcohols, ethers, andesters, the latter including alkyl halides, alkyl sulfates, alkylphosphates, and various esters of carboxylic acids. The preferredolefinacting compounds are olefinic hydrocarbons which comprisemonoolefins containing one double bond per molecule and polyolefinswhich contain more than one double bond per molecule. Monoolefins whichare utilized as olefin-acting compounds in the process of the presentinvention are either normally gaseous or normally liquid and includeethylene, propylene, l-butene, 2-butene, isobutylene, and highermolecular weight normally liquid olefins such as the various pentenes,hexenes, heptenes, octenes, and mixtures thereof, and still highermolecular weight liquid olefins, the latter including various olefinpolymers having from about 9 to about 18 carbon atoms per moleculeincluding propylene trimer, propylene tetramer, propylene pentamer, etc.Cycloolefins such as cyclopentene, methylcyclopentene, cyclohexene,methylcyclo hexene, etc. may also be utilized. Also included within thescope of the olefin-acting compound are certain substances capable ofproducing olefinic hydrocarbons or intermediates thereof under theconditions of operation utilized in the process. Typicalolefin-producing substances or olefinacting compounds capable of useinclude alkyl halides capable of undergoing dehydrohalogenation to formolefinic hydrocarbons and thus containing at least two carbon atoms permolecule. Examples of such alkyl halides include ethyl fluoride,n-propyl fluoride, tertbutyl fluoride,

etc., ethyl chloride, n-propyl chloride, isopropyl chloride,

n-butyl chloride, isobutyl chloride, secbutyl chloride, tertbutylchloride, etc., ethyl bromide, n-propyl bromide, isopropyl bromide,n-butyl bromide, isobutyl bromide, secbutyl bromide, tert-butyl bromide,etc. As stated hereinabove, other esters such as alkyl sulfatesincluding ethyl sulfate, propyl sulfate, etc., and alkyl phosphatesincluding ethyl phosphates, etc. may also be utilized. Ethers such asdiethyl ether, ethyl propyl ether, dipropyl ether, etc., are alsoincluded within the generally broad scope of the term olefin-actingcompound and may be successfully utilized as alkylating agents in theprocess of this invention.

In addition, the process of this invention may be successfully appliedto and utilized for complete conversion of olefin hydrocarbons whenthese olefin hydrocarbons are present in minor quantities in various gasstreams. Thus, the normally gaseous olefin for use in the process ofthis invention need not be concentrated. Such normally gaseous olefinhydrocarbons appear in minor quantities in various refinery gas streams,usually diluted with gases such as hydrogen, nitrogen, methane, ethane,propane, etc. These gas streams containing minor quantities of olefinhydrocarbons are obtained in petroleum refineries from various refineryinstallations including thermal cracking units, catalytic crackingunits, thermal reforming units, coking units, polymerization units,dehydrogenation units, etc. Such refinery gas streams have in the pastoften been burned for fuel value, since an economical process for theutilization of their olefin hydrocarbon content has not been available.This is particularly true for refinery gas streams known as off-gasstreams containing relatively minor quantities of olefin hydrocarbonssuch as ethylene, propylene, etc.

As hereinbefore set forth, the invention is concerned with a process forthe alkylation of alkylatablc aromatic compounds, said process beingeffected in the presence of a catalyst which possesses a high degree ofhydrocarbon conversion activity and is particularly effective as analkylation catalyst for alkylatable aromatic compounds, a representativenumber of which are hereinabove set forth. The catalyst comprises arefractory inorganic oxide chemically combined with a metal subfiuoridevapor. Satisfactory refractory oxides for the preparation of catalystsfor use in the process of this invention include high surface areacrystalline alumina modifications such as gamma-, etaand theta-alumina,although these are not necessarily of equivalent suitability. By theterm high surface area is meant a surface area measured by surfaceadsorption techniques within the range of from about 25 to about 500 ormore square meters per gram and preferably a surface area ofapproximately 100 to 300 square meters per gram. In addition to theaforementioned gamma-, etaand theta-aluminas which may be utilized assolid supports, it is also contemplated that other refractory oxidessuch as silica, zirconia, magnesia, thoria, etc., and combinations ofretractory oxides such as silicaalumina, silica-magnesia,alumina-silica-magnesia, alumina-thoria, alumina-zirconia, etc., mayalso be utilized as solid supports for the catalyst of the presentinvention.

As set forth hereinabove, the catalyst comprises a refractory inorganicoxide that is combined with a metal subfiuoride vapor to effect chemicalcombination of the refractory inorganic oxide with said metalsubfiuoride vapor. Particularly preferred metal subfiuorides include thealuminum subfiuorides including aluminum monolluoride and siliconsubfluorides including silicon difluoride due mainly to the relativeease in preparing these compounds although the invention is notrestricted to their use, but may employ any of the known metalsubfluorides insofar as they are adaptable. However, it is not intendedto infer that different metal subfiuorides which may be employed willproduce catalysts which have identical effects upon any given organicreaction as each of the catalysts roduced from different metalsubfiuorides and by slightly varying procedures will exert its owncharacteristic action.

It is a feature of the present invention that the finished catalyst ofthe present invention prepared as hereinafter set forth has increasedstructural strength and a high degree of stability due to the immobilityof the components of the finished catalysts inasmuch as chemicalcombination of the refractory inorganic oxide with the metal subfiuoridevapor is accomplished as hereinafter described.

The catalyst of the present invention comprises a metal subfiuoridevapor chemically combined with the refractory inorganic oxide so as toeffect chemical combination of the refractory inorganic oxide with themetal subfluoride vapor, and as hereinbefore set forth, it is theparticular association of these components which results in the unusualcatalytic properties of this catalyst. The metal subfiuoride vapor maybe chemically combined with the refractory inorganic oxide attemperatures in the range of 650 C. to about 1200 C. and at a pressureof from about subatmospheric to about 7 atmospheres. The formation ofthe metal subfiuoride vapor, and especially the formation of aluminummonofiuoride is accomplished by sweeping with a gas such as helium,argon or hydrogen, and preferably helium, a stoichiometric mixture ofaluminum metal (melting point about 660 C.) and aluminum trifluoride(melting point greater than 1000 C.) which is heated to about 750 to 800C. The refractory inorganic oxide which is then chemically combined withthe aluminum monofiuoride is placed in the downstream helium flow. Thechemical combination takes place at temperatures in excess of 650 C.Fluoride concentrations of between 0.01 percent to about 5 percent (byweight) are preferred.

In an alternative method, the catalyst may be prepared by pelleting amixture of aluminum powder with a stoichiometric excess of aluminumtrifiuoride, and mixing these pellets with the refractory inorganicoxide catalyst support and then heating in vacuum in a furnace tube atelevated temperatures.

The process of this invention utilizing the catalyst hereinbefore setforth may be effected in any suitable manner and may comprise either abatch or a continuous type operation. The preferred method by which theprocess of this invention may be effected is a continuous typeoperation. One particular method is the fixed bed operation in which thealkylatable aromatic compound and the olefin-acting compound arecontinuously charged to a reaction zone containing a fixed bed of thedesired catalyst, said zone being maintained at the proper operatingconditions of temperature and pressure, that is, a temperature in therange of from about 0 to about 450 C. or more and a pressure including apressure of from about atmospheric to about 200 atmospheres or more. Thecatalyst is suitable for either gas phase or liquid phase reactions sothat the liquid hourly space velocity (the volume of charge per volumeof catalyst per hour) may be maintained in the reaction zone in therange of from about 0.1 to about 20 or more, preferably in the range offrom about 0.1 to about 10, or at a gaseous hourly space velocity in therange of from about 100 to about 1500 or more. The reaction zone maycomprise an unpacked vessel or coil or may be lined with an adsorbentpacking material. The two reactants may be charged through separatelines or, if so desired, may be admixed prior to entry into saidreaction zone and charged thereto in a single stream. This charge passesthrough the catalyst bed in either an upward or downward flow and thealkylated product is continuously withdrawn, separated from the reactoreffluent, and recovered, while any unreacted starting materials may berecycled to form a portion of the feed stock. It is also contemplatedwithin the scope of this invention that reaction gases such as nitrogen,argon, hydrogen, helium, etc., may also be charged to the reaction zoneif desired. Another continuous type operation comprises the moving bedtype in which the reactants and the catalyst bed move eitherconcurrently or countercurrently to each other while passing throughsaid reaction zone.

Still another type of operation which may be used is the batch typeoperation in which a quantity of the alkylntable aromatic hydrocarbon,the olefin-acting compound and the catalyst are placed in an appropriateapparatus such as, for example, a rotating or stirred autoclave. Theapparatus is then heated to the desired temperature and maintainedthereat for a predetermined residence time at the end of which time theflask and contents thereof are cooled to room temperature and thedesired reaction product is recovered by conventional means, such as,for example, by washing, drying, fractional distillation,crystallization, etc.

The following examples are given to illustrate the process of thepresent invention which, however, are not intended to limit thegenerally broad scope of the present invention in strict accordancetherewith.

EXAMPLE I A quartz vessel with provisions for connection to a vacuumsystem was filled with a mixture of about 50 grams of ,3 inch aluminaspheres and about 10 grams of /8 inch pellets comprising about 20%aluminum metal and about aluminum monofiuoride by weight. The contentsof the vessel were outgassed at a pressure of less than l0- mm. whileslowly being heated in a tube furnace. Approximately 4 hours wereallowed for the EXAMPLE II In this example, a volatile fluoride (800 C.)was prepared by sweeping with helium a stoichiometric mixture ofaluminum metal (melting point 660 C.) and aluminum trifluoride (meltingpoint greater than 1000 C.) which was heated to 750800 C. Aluminummonofluoride was then produced. A catalyst base in the form of ,4 inchalumina spheres was then placed in the downstream helium flow and thealuminum monofluoride was chemically combined with the alumina base at atemperature in excess of 650 C.

The catalyst produced by this vapor deposition and chemical combinationof the aluminum monofluoride with the alumina had fluoride levels ofbetween 0.01 and 1.1 percent by weight of fluoride chemically combinedtherewith. This catalyst was designated as catalyst B.

EXAMPLE III The catalyst prepared according to Example I above anddesignated as catalyst A is utilized in an alkylation reaction todetermine the alkylation activity of said catalyst. In this experiment,a portion of the catalyst prepared according to the method of Example Iis placed in an appropriate apparatus which is provided with heatingmeans. In the experiment, benzene and ethylene are charged separately tothe alkylation reaction zone. The reactor is maintained at about 500p.s.i.g. and 125 C. Substantial conversion of the ethylene is obtained.The product is analyzed for olefins using a mass spectrometer and it isfound that the product comprises ethylbenzene, diethylbenzene,polyethylbenzenes and unreacted benzene.

EXAMPLE IV The catalyst prepared according to Example 11 and designatedas catalyst B is utilized in the alkylation reaction zone, a portion ofthe finished catalyst being placed in the alkylation apparatus. In theexperiment, benzene and ethylene are charged separately to thealkylation zone which is maintained at about 500 p.s.i.g. and 125 C.Based on weight, substantial conversion of the ethylene is obtained. Theproduct is analyzed for olefins using a mass spectrometer and it isfound that the product comprises ethylbenzene, diethylbenzene,polyethylbenzenes and unreacted benzene.

EXAMPLE V The catalyst prepared according to Example I and designated ascatalyst A is utilized in an alkylation reaction, a second portion ofthe finished catalyst being place in the alkylation apparatus. In theexperiment, benzene and propylene are charged separately to thealkylation zone. The reactor is maintained at about 400 p.s.i.g. and 175C. Substantial conversion of the propylene is obtained. The product isanalyzed for olefins using a mass spectrometer and it is found that theproduct comprises cumene, diisopropylbenzene, polypropylbenzenes andunreacted benzene.

6 EXAMPLE VI A second portion of catalyst prepared according to ExampleII above and designated as catalyst B is utilized in an alkylationreaction to determine the alkylation activity of said catalyst. In theexperiment, benzene and pentene-l were charged separately to thealkylation reaction zone. The reactor was maintained at about 450p.s.i.g. and 150 C. Substantial conversion of the pentene-l wasobtained. The product was analyzed for olefins using a mass spectrometerand it is found that the major product comprised Z-phenylpentane.

EXAMPLE VII A third portion of the catalyst prepared according toExample I above and designated as catalyst A is utilized in thealkylation of benzene with a synthetic refinery olfgas similar to thatnormally observed from a catalytic cracking unit. A fresh batch of thecatalyst is placed in an alkylation reactor and the reactor ismaintained at a temperature in the range of from about C. to about 215C. at a pressure of about 600 p.s.i.g. The composition of the syntheticofl-gas feed is as follows: carbon dioxide, 0.1 mol percent; nitrogen,29.0 percent; carbon monoxide, 1.3 mol percent; hydrogen, 18.9 molpercent; methane, 35.0 mol percent; ethylene, 12.0 mol percent; ethane,0.5 mol percent; propylene, 2.5 mol percent; propane, 0.1 percent;isobutane, 0.1 mol percent; and acetylene, 0.5 mol percent. The off-gasand benzene are charged separately to the alkylation zone. The plantliquid eflluent is tested for unsaturation and is found to have a lowbromine index indicating the substantial absence of olefinpolymerization products. The product comprises ethylbenzene,diethylbenzene, polyethylbenzenes, cumene, diisopropylbenzene,polypropylbenzenes and 1,1-diphenylethane.

I claim as my invention:

1. A conversion process which comprises alkylating an alkylatablearomatic compound with an olefin-acting compound at a temperature in therange of from about 0 to about 450 C. and at a pressure in the range offrom about atmospheric to about 200 atmospheres in contact with acatalyst comprising a refractory inorganic oxide chemically combinedwith a metal subfluoride vapor.

2. The process of claim 1 further characterized in that said metalsubfluoride is aluminum monofluoride.

3. The process of claim 2 further characterized in that said refractoryinorganic oxide comprises alumina.

4. The process of claim 2 further characterized in that said refractoryinorganic oxide comprises silica-alumina.

5. The process of claim 4 further characterized in that said alkylatablearomatic compound is an alkylatable benzene hydrocarbon.

6. The process of claim 4 further characterized in that said alkylatablearomatic compound is benzene.

7. The process of claim 4 further characterized in that saidolefin-acting compound is an olefinic hydrocarbon.

8. The process of claim 4 further characterized in that saidolefin-acting compound is a normally gaseous olefin.

9. The process of claim 8 further characterized in that said normallygaseous olefin is ethylene.

10. The process of claim 8 further characterized in that said normallygaseous olefin is propylene.

References Cited UNITED STATES PATENTS DELBERT E. GANTZ, PrimaryExaminer.

CURTIS R. DAVIS, Assistant Examiner.

